Dear Mel
Good to see you applying your excellent critical faculties again. A few
comments....
In message <[log in to unmask]>, [log in to unmask] writes
>Recently we discussed the proliferation of some very dubious and incorrect
>biomechanics in various journal articles. A book that is quite often
>recommended by the Cooper Institute and other fitness organisations for
>personal trainers is "Muscle Mechanics" (Aaberg E Human Kinetics 1998)
>contains the following further gems of pseudo biomechanics. My comments
>below these extracts serve as a partial book review.
>
><<1. To perform resistance training, there must first be a
>resistance....Some may visualize dumbbells, barbells and metal plates.
>Others may think more of pulleys, cables and machines. Though different,
>these are all weights with gravity providing the actual resistance. (page 7)
>>>
>
>*** The idea that gravity somehow provides some sort of invisible resistance
>is rife in the fitness world. It is clear that many fitness lecturers do not
>know what is meant by "gravity" and certainly do not know the difference
>between "inertial force", "gravitational force", "weight" and "mass". They
>need to know that a massive object exerts a force known as "gravitational
>force" on another massive object by virtue of the two masses involved,
>according to the equation:
>
>Force F = GMm/R^2 (or G*M*m divided by R squared)
>
>where G is the 'gravitational constant', M and m are the masses of the bodies
>attracting one another via gravity and R is the distance separating the
>bodies.
>
>On the surface of the Earth, the gravitational force tends to accelerate a
>body on its surface with an acceleration of g (about 9.8 metres per second
>squared). Gravity does not "provide the actual resistance" - the mass of the
>Earth produces a gravitational acceleration that acts on the weight that we
>are lifting (and vice versa), thereby producing what is known as the "weight"
>of the mass or load at that specific location on the Earth.
>
>If we are to be pedantic, the weight of a given load is less at the poles
>than the equator, since the radius R of the earth is greater at the equator
>than the poles. It is very misleading and totally incorrect to even
>popularise gravity as being some sort of "resistance". That is way off
>course.
>
John Spencer: There is some justification for writing about
gravitational resistance as a means of 'common parlance'. Our language
is replete with terms that are technically incorrect but understood by
all. If I was to say that I would meet you at sunrise tomorrow would you
counter that was a technically incorrect perception of the actual
science as the sun only appeared to rise above the horizon and that in
fact it was an illusion due to the relative movements of...etc.etc....
or would you set your alarm clock for 5.30am?
Certainly if gravity was taken out of the equation there would be no
resistance so these exercises are gravity dependent. In physiotherapy we
talk about gravity-assisted exercises and gravity-resisted exercises for
instance which might be technically incorrect but is a useful way to
communicate. As our job is to explain things to the public (not science
teachers) this seems to work well.
><<2. Dynamic Constant Resistance. In this type of training, the resistance
>used is constant. The most common examples of this would be free weights and
>certain machines that use only round pulleys or rollers to redirect the
>resistance, but they do not alter the resistance during exercise. (page 7) >>
>
>***Machine manufacturers have been using this faulty reasoning to promote
>their 'variable resistance' products for many years. The fact is that, while
>the mass or load on the bar or machine may be constant, the resistance
>offered to the exerciser depends on the acceleration of the load. Skilled
>trainees even alter this resistance voluntarily by using the method of CAT
>(Compensatory Acceleration Training). Weights are NOT constant resistance
>training devices; they are constant MASS devices.
>
John Spencer: Technically, isn't this what the author is saying ie the
resistance offered by the weight is constant ie these weights and
machines themselves "do not alter the resistance during exercise". There
is no denial that the user of the machine may introduce an element of
altered resistance by accelerating the load but it is not the machine or
the weight itself which does this. So if F=m x a the weight offers a
constant mass and the user chooses to alter the acceleration.
><<3. Isokinetic Resistance. Isokinetics refers to the contraction of a
>muscle performed at a constant angular velocity. This means that the speed
>at which the muscle lengthens and shortens is constant, but not necessarily
>the resistance. The motion cannot be accelerated. Any force applied in an
>attempt to increase velocity results in an equal reaction force. These
>opposing forces will mirror each other throughout the range of motion. (page
>8) >>
>
>***First of all, all physiology texts state that a muscle can only contract
>or relax, but never lengthen. (note very well we are not talking about
>possible lengthening of the muscle COMPLEX which contains collagenous
>elements such as tendons, which can lengthen under certain conditions). This
>point is made in Physiology 101 or even in high school biology courses.
>
John Spencer: I think there is confusion here between an individual
muscle fibre and the entire anatomical structure we call a muscle.
Certainly physiological textbooks by eminent authors refer to muscles
shortening and lengthening (see for instance "Human Anatomy" Vander,
Sherman & Luciano - two of whom are professors of physiology at Michigan
University ""When the force is great enough, the bone moves as the
muscle shortens" pg 311). If these guys use these terms surely we cannot
be surprised if they are used in less erudite texts?
I don't understand how a muscle (say biceps brachii), measured from
musculotendinous insertion to musculotendinous insertion, cannot be said
to be longer at end of range elbow extension then at end of range elbow
flexion?
>Besides the fact that the author regularly interchanges speed and velocity,
>there are several other errors in his understanding of isokinetics - would
>others care to analyse them for fun?
>
><<4. ...what many people call a dumbbell arm curl shall be listed as a
>dumbbell biceps flexion or dumbbell biceps flex." (page 6) >>
>
>*** This suggests that elbow flexion is carried out exclusively by the
>brachial biceps. This is not even vaguely acceptable, because elbow flexion
>is associated with action of the biceps, brachialis and brachioradialis.
>Moreover, the use of terms such as flex or flexion in functional anatomy
>refers to joints not muscles.
>
John Spencer: I don't see why these terms imply exclusivity of biceps
brachii just that it is a prominent and most visible elbow flexor. If
one insisted on lFrom [log in to unmask] Tue Sep 12 23:05:46 2000
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Subject: Re: Shin splints
From: John Spencer <[log in to unmask]>
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Dear Luke
How about more details of the taping. Scan us a photo maybe or two?
In message <[log in to unmask]>, luke harris
<[log in to unmask]> writes
>although the words "in my experience" coming from a 19 year old might
>bring a wry smile to the faces of some...
>
>i work for aussie rules football team, and one of my players came to
>me complaining of 'shin splints'. now, i was aware that 'shin splints'
>is a rather broad term and can mean different things to different
>people, so i decided to have a peek anyway and see what i could learn.
>
>the basic result was that the pain came on shortly after commencing
>physical activity and took up to a few hours to ease after stopping
>the activity (but obviously not as long to ease when the activity was
>ceased earlier). the pain was aggravated on active plantarflexion,
>isometric contraction of plantarflexors, and nor present on passive
>plantarflexion.
>
>i spoke to one of my colleagues at uni (a qualified podiatrist with 15
>years clinical experience who has decided to make a career chaneg -
>and is now in second year physio) about this, and if he had any
>recommendations. he showed me a type of taping which is essentially a
>few stirrup-like strips, from the level of insertion of the affected
>muscle, over a low-dye base. (there's a little more too it, but that's
>put nice and simply).
>
>i went back to my player, applied this taping technique, and as if by
>miracle the pain did not occur during training. so i repeated this
>method for training sessions and games and he had no complaints.
>
>now there is cause here for some of you to say "the problem may have
>resolved prior to the first taping, and so there was no problem
>present for the tape to be acting on". well, some training nights when
>i wasn't able to be there, he played without the tape, and experienced
>these problems. so that kinda supports it effectiveness.
>
>one of my friends also works for a junior footy team, and two weeks
>ago, when she was unable to be at the game, i filled in for her. one
>of her players was also complaining of 'shin splints'. after a quick
>examination (yeilding a similar pattern to my player), i felt that
>attempting this same technique on him was justified... and it worked
>brilliantly! he didn't complain of the problem at all during or after
>the game. i think he was more amazed than anyone.
>
>so, although this may not be helping the condition in the long-run, it
>seemed to help these individuals to the extent that they could play a
>full game pain-free. both of these individuals were complaining of
>tibialis posterior pain, and so i'm eager to find an athlete with
>tibialis anterior 'shin splints' to see if they'll let me attempt the
>same technique on them.
>
>this message was proudly brought to you by ...
>luke harris of benzene - http://benzene.cjb.net/
>prefer email sent to me at [log in to unmask]
>
>__________________________________________________________________
>Get your free Australian email account at http://www.start.com.au
>
--
John Spencer
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abelling all the muscles that might act to flex the
elbow joint it would become an unwieldy list (including a fourth muscle
you have missed from your list...but now I'm being clever...). Certainly
this is more descriptive than 'biceps curl' when nothing actually curls.
><<5. Yet another possibility is that a muscle could be contracting
>isometrically while it neither shortens nor lengthens. >>
>
>*** It is also a very common misconception that an isometric muscle action is
>not associated with muscle contraction or shortening. While an isometric
>action produces no external movement of the joint, the muscle is very
>definitely is contracting within the body.
John Spencer: Isn't this what they are saying..that the muscle IS
contracting in isometric activity?
PS haven't you just used the word 'shortening' in your reply here...I
understood you to be saying muscles couldn't be talked about as
lengthening or shortening? (I may have misunderstood here as actually
you deny the terminology of lengthening, not specifically shortening)
>
><<6. ..A degree of force angle must be present before a muscle can have much
>biomechanical advantage in performing any loaded joint motion. Therefore, it
>is important not to fully extend or lock any joint during resistance-training
>exercises. (page 40) >>
>
>*** One might ask how one should execute many of the weightlifting and
>powerlifting exercises and their numerous variations if one should not lock
>the joints? This belief has been around the aerobics floor for many years
>and it is most surprising that some 'experts' still believe it. As a simple
>example, try ordinary walking without locking the knee, in particular - it
>looks and feels hilarious. I, for one, would also be terrified of snatching
>with my elbows and shoulders unlocked at the end of the movement!. There
>is much more room for further comment here - any offers?
John Spencer: Well, I would argue that actually it looks pretty strange
to 'lock' your knees (ie into full extension) when you walk. In normal
gait the 'screw home' mechanism of the tibio-femoral joint is engaged
but not fully... stand up and try it now. If you walked round fully
'locking' your knee back you would get sore pretty quick. As for the
shoulder, as a ball and socket joint I can't see it has a 'locking'
action. Do you really take your shoulders back into full extension (ie
way past the vertical) when you snatch... pretty unstable I'd think.
>
><<7. For most people, conducting singular-plane joint movements is
>preferable to multiple-plane joint movements with most resistance-training
>exercises. The reasoning for this goes back to the same two principles this
>book is based on - efficiency and safety. >>
>
>*** Just an opening comment about terminology - there is no such entity as
>"singular-plane" - the recognised term is "single-plane" or "uniplanar".
>The author regularly misquotes standard terminology like that, but I have not
>focused on this, because these minor transgressions merely serve to act as
>pointers that the author is not very conversant with working in the field of
>biomechanics and functional anatomy.
>
>I would like others to comment on the main point in this quotation, since it
>has some major implications for all resistance training. At the very least,
>we must stress that multiple joint, multiple plane action tends to be more
>efficient and often less stressful on the joints than uniplanar, isolated
>joint action.
John Spencer: Is there such a thing as uniplanar, isolated joint action?
>Even many physical therapists are now acknowledging this fact
>by advocating "closed chain" e.g. free standing squats) instead of "open
>chain" exercises (e.g. seated 'knee extensions').
>
>Even though the title of the book is "Muscle Mechanics" and the first chapter
>is called "The Principles of Muscle Mechanics" , there is not a single
>paragraph or sketch explaining the mechanics of muscle action, nor a single
>sentence about the relationship between muscle mechanics and strength,
>hypertrophy, flexibility and other fitness qualities. It is clear that the
>title was chosen simply for the sound of the term rather than its
>relationship to the topic of muscle mechanics.
>
>Most of the book is devoted to illustrations of about 73 different exercises,
>many of them using the physio ball and various gym machines. Many of these
>exercises are replete with errors and some of them are of dubious safety for
>the average person (such as straight leg raises off the end of a bench).
>Most fascinating of all is that the entire section on trunk and abdominal
>exercise does not even mention any role for the quadratus lumborum and
>transversus muscles, something that virtually no other book on trunk training
>and stabilisation manages to do.
>
>Other than complimenting the book for being well illustrated and attractively
>packaged, no quality-concerned lecturer could advocate the use of this text
>as a serious reference for personal trainers, especially since the author
>declares that:
>
>"You can easily see how training properly by using 'Muscle Mechanics' could
>be the most important thing you've ever done for the integrity of your body"
>(p 4). .....and .....
>
>"Also be sure that the trainer you interview is familiar with the davanced
>techniques and exercise specifics presented in this book." (p 8).
>
>If one is going to extol the virtues of one's own book in that manner, then
>it has to be subjected to special scrutiny to determine the accuracy of those
>claims.
>
>There are several free websites that give you far superior training
>information than this. Would anyone care to list their favourites here?
>
>Dr Mel C Siff
>Denver, USA
John Spencer: I don't doubt that you have to rejoinders to my comments
forming already Mel so come on.... let's rumble!
--
John Spencer
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